Ligand-Induced Electronic Structure Modulation of Self-Evolved Ni₃S₂ Nanosheets for the Electrocatalytic Oxygen...

Modulating the electronic structure of the electrocatalyst plays a vital role in boosting the electrocatalytic performance of the oxygen evolution reaction (OER). In this work, we introduced a one-step solvothermal method to fabricate 1,1-ferrocene dicarboxylic acid (FcDA)-decorated self-evolved nickel sulfide (Ni₃S₂) nanosheet arrays on a nickel foam (NF) framework (denoted as FcDA-Ni₃S₂/NF). Benefiting from the interconnected ultrathin nanosheet architecture, ligand dopants induced and facilitated in situ structural reconstruction, and the FcDA-decorated Ni₃S₂ (FcDA-Ni₃S₂/NF) outperformed its singly doped and undoped counterparts in terms of OER activity. The optimized FcDA-Ni₃S₂/NF self-supported electrode presents a remarkably low overpotential of 268 mV to achieve a current density of 10 mA cm^-2 for the OER and demonstrates robust electrochemical stability for 48 h in a 1.0 M KOH electrolyte. More importantly, in situ electrochemical Raman spectroscopy reveals the generation of catalytically active oxyhydroxide species (NiOOH) derived from the surface construction during the OER of pristine FcDA-Ni₃S₂/NF, contributing significantly to its superior electrocatalytic performance. This study concerns the modulation of electronic structure through ligand engineering and may provide profound insight into the design of cost-efficient OER electrocatalysts.